The present invention relates to a device for attaching electrodes to a subject for stimulating abdominal muscles by electrotherapy, and the invention also relates to a device for stimulating abdominal muscles by electrotherapy. The invention further relates to an electrotherapeutic method for stimulating abdominal muscles, and to a fastener for use in the device.
Electrotherapy is commonly used for stimulating abdominal muscles for improving and toning the muscles, and for the relief of pain. Known electrotherapeutic methods and devices require that a pulsed signal be passed subcutaneously through the subject between a pair of electrodes which typically, are aligned with the muscle to be stimulated for defining a current path between the electrode which is co-linear with the direction of the muscle. In known electrotherapeutic devices and methods, it is necessary to provide a relatively large number of electrode pairs for stimulating the more important abdominal muscles, for example, the central rectus abdominis muscle, and the transversalis and oblique muscles. Typically, one or two pairs of electrodes are required located on respective opposite sides of the umbilicus for stimulating the rectus abdominis muscle, and two obliquely located electrode pairs are required towards the respective sides of the abdominal region for stimulating the transversalis and oblique muscles on the respective sides of the abdomen. Thus, in order to stimulate the rectus abdominis muscle, the transversalis and oblique muscles, three to four electrode pairs are required. This, leads to a number of disadvantages, in that firstly, unless extreme care is taken in locating the electrodes on the abdomen of the subject some or all of the electrodes can readily easily be misaligned with the respective muscles or displaced therefrom, thus, leading to significant inefficiencies and indeed in extreme cases ineffectual treatment. Secondly, because of the high number of electrode pairs, a relatively complex signal generator is required for providing appropriately pulsed signals so that the pulsed signals only travel between the respective pairs between which the pulsed signals are to travel subcutaneously in the subject. Thirdly, in many cases there is a danger of transthoracic current paths being defined by the electrodes, which in certain cases can lead to transthoracic currents within the subject, which in extreme cases may cause cardiac arrhythmias. The possibility of misalignment of the electrode pairs further increases the risk of transthoracic currents being passed through the subject.
There is therefore a need for a device for attaching electrodes to a subject for stimulating abdominal muscles and in particular for stimulating the rectus abdominis, the transversalis and the oblique muscles, which overcomes these problems. There is also a need for an electrotherapeutic device and a method for stimulating abdominal muscles which overcomes these problems.
The present invention is directed towards providing such a device for attaching electrodes to a subject, such an electrotherapeutic device and method for stimulating abdominal muscles of a subject. The invention is also directed towards providing a fastener for use in the device.
According to the invention there is provided a device for attaching at least three electrodes to a subject for stimulating abdominal muscles of the subject, the device comprising an attachment means for extending around the torso of the subject, wherein a main locating means is provided on the attachment means for locating a central electrode of the at least three electrodes adjacent the umbilicus of the subject, and two secondary locating means are provided on the attachment means disposed on respective opposite sides of the main locating means for locating two corresponding side electrodes of the at least three electrodes spaced apart from the central electrode in a general direction towards a corresponding one of the left and right mid-axillary lines of the torso intermediate the rib cage and corresponding left and right iliac crests so that by applying at least one pulsed signal to the subject through the respective central and side electrodes abdominal muscles of the subject are stimulated.
In one embodiment of the invention the secondary locating means are disposed on the attachment means for locating the respective side electrodes towards the mid-point of the corresponding mid-axillary line between the rib cage and the corresponding iliac crest. Preferably, the secondary locating means are disposed on the attachment means for locating the respective side electrodes adjacent the corresponding mid-axillary line.
Ideally, the secondary locating means are disposed on the attachment means for locating the respective side electrodes adjacent the mid-point of the corresponding mid-axillary line between the rib cage and the corresponding iliac crest.
Preferably, the main locating means is disposed on the attachment means for locating the central electrode on the umbilicus and extending around the umbilicus. Advantageously, the main locating means is disposed on the attachment means for locating the central electrode on the umbilicus and extending completely around the umbilicus.
In one embodiment of the invention the main locating means is disposed on the attachment means for locating the central electrode on the umbilicus, but with a greater area of the central electrode located below the umbilicus than above the umbilicus.
In another embodiment of the invention the main locating means is disposed on the attachment means for locating the central electrode adjacent but not on the umbilicus.
In a further embodiment of the invention the main locating means is disposed on the attachment means for locating the central electrode below the umbilicus.
In a still further embodiment of the invention the main locating means is disposed on the attachment means for locating the central electrode above the umbilicus.
In a further embodiment of the invention the main locating means is disposed on the attachment means for locating the central electrode both below and above the umbilicus.
In one embodiment of the invention a reference means is provided on the attachment means for locating the attachment means on the torso relative to an anatomical reference. Preferably, the reference means is provided for locating the attachment means circumferentially around the torso. Advantageously, the reference means is provided for locating the attachment means vertically along the torso.
In one embodiment of the invention the main locating means acts as the reference means for locating the attachment means relative to the anatomical reference provided by the umbilicus.
In another embodiment of the invention the main locating means comprises a first main locating means and a second main locating means for locating respective corresponding first and second central electrodes adjacent the umbilicus of the subject.
Advantageously, the first main locating means is provided for locating the first central electrode above the umbilicus, and the second main locating means is provided for locating the second central electrode below the umbilicus.
In another embodiment of the invention two sets of at least two secondary locating means are disposed on the respective opposite sides of the main locating means for facilitating selective location of the respective side electrodes for accommodating different girths of torso.
Advantageously, each set of secondary locating means comprises three secondary locating means.
In another embodiment of the invention portions of the attachment means on respective opposite sides of the main locating means between the main locating means and the corresponding secondary locating means are of resilient material for facilitating resilient stretching of the attachment means between the main and corresponding secondary locating means. Preferably, the attachment means is of a resilient material for facilitating stretching of the attachment means around the torso, the resilient portions of the attachments means being of greater stretchability than that of the rest of the attachment means.
In one embodiment of the invention a main electrically conductive contact means is provided on the attachment means corresponding to each main locating means for receiving the at least one pulsed signal and for relaying the signal to the corresponding central electrode. Preferably, each main contact means is located within the corresponding main locating means.
In another embodiment of the invention two secondary electrically conductive contact means are provided on the attachment means for receiving the at least one pulsed signal and for relaying the signal to the respective corresponding side electrodes. Advantageously, each secondary contact means is located adjacent the corresponding secondary locating means or the corresponding set of secondary locating means.
In another embodiment of the invention each secondary contact means is located adjacent the corresponding set of secondary locating means so that irrespective of which secondary locating means is selected for locating the corresponding side electrode the side electrode is in electrically conductive engagement with the secondary contact means.
Advantageously, each main and secondary locating means is provided by a visually perceptive locating means. Preferably, each main and secondary locating means is formed by a corresponding locating mark on the attachment means.
Ideally, each locating mark defines an outline of a part of the periphery of the corresponding electrode corresponding to the locating means.
In one embodiment of the invention each locating means is adapted for locating a patch type electrode.
In another embodiment of the invention the device comprises the at least three electrodes. Preferably, each electrode is a patch type electrode.
In one embodiment of the invention each side electrode is sized to cover at least a portion of the corresponding lower thoracic nerves and the corresponding first and second lumbar nerves.
In another embodiment of the invention each central electrode is sized to extend substantially across the rectus abdominus muscle.
Advantageously, each electrode defines an area of contact over which the electrode makes direct electrical contact with the subject, the area of contact of each side electrode being such as not to exceed the area of contact of the or both central electrodes. Preferably, the area of contact of each side electrode does not exceed one third of the area of contact of the or both central electrodes.
In one embodiment of the invention each side electrode is of width in a circumferential direction relative to the torso of the subject in the range of 50 mm to 150 mm, and is of length in a vertical direction relative to the torso of the subject in the range of 80 mm to 120 mm.
In one embodiment of the invention a first electrically conductive coating is provided on one side of each electrode for electrically connecting the electrode to the corresponding contact means. Advantageously, the first coating is a gel type coating containing an electrolyte solution for enhancing electrical contact between the electrode and the corresponding contact means.
In another embodiment of the invention a second electrically conductive coating is provided on the other side of each electrode for electrically connecting the patch electrode and the torso of the subject. Preferably, the second coating is a gel type coating.
In one embodiment of the invention the second coating is an adhesive coating.
In another embodiment of the invention the first coating is an adhesive coating.
Advantageously, the bond strength of the first coating to the attachment means is greater than the bond strength of the second coating to the torso for facilitating removal of the attachment means and the electrodes located thereon from the torso of the subject.
Preferably, the electrodes are pre-coated with the respective first and second adhesive coatings.
In one embodiment of the invention a receiving means is provided in the attachment means for receiving a signal generating means for generating the at least one pulsed signal.
Preferably, a main electrical connecting means extends between the receiving means and each main contact means for relaying the at least one pulsed signal from the signal generating means to the corresponding main contact means.
Advantageously, a secondary electrical connecting means extends between the receiving means and each secondary contact means for relaying the at least one pulsed signal from the signal generating means to the corresponding secondary contact means.
Ideally, each electrical connecting means is located within the attachment means.
In one embodiment of the invention the receiving means is a releasable receiving means for releasably receiving the signal generating means.
Advantageously, the receiving means receives the signal generating means with a snap fit action.
In one embodiment of the invention the signal generating means for generating the at least one pulsed signal is provided in the receiving means.
In one embodiment of the invention a means is provided for selectively selecting at least one pair of electrodes from the at least three electrodes through which the at least one pulsed signal is applied to the subject.
In another embodiment of the invention the at least one pulsed signal is applied simultaneously to each of the selected pairs of electrodes. Alternatively, the at last one pulsed signal is applied sequentially to each of the selected pairs of electrodes.
In one embodiment of the invention one of the selected pairs of the electrodes comprises one side electrode and the central electrode, and another selected pair of the electrodes comprises the other side electrode and the central electrode.
In another embodiment of the invention one of the selected pairs of electrodes comprises the two side electrodes.
In another embodiment of the invention one of the selected pairs of electrodes comprises one of the side electrodes and one of the first and second central electrodes, and another of the selected pairs of electrodes comprises the other of the side electrodes and the other of the first and second central electrodes.
In a further embodiment of the invention one of the selected pairs of electrodes comprises the first and second central electrodes which act as one single electrode and one of the side electrodes, and another of the selected pairs of electrodes comprises the first and second central electrodes which act as one single electrode and the other side electrode.
In a still further embodiment of the invention one of the selected pairs of electrodes comprises the first and second central electrodes.
In one embodiment of the invention the pulsed signals generated by the signal generating means for applying to the respective pairs of electrodes may be the same or different.
In one embodiment of the invention each pulsed signal comprises a plurality of pulses at intervals in the range of 5 milliseconds to 1000 milliseconds. Preferably, each pulsed signal comprises a plurality of pulses at intervals in the range of 20 milliseconds to 40 milliseconds.
Advantageously, each pulsed signal comprises a plurality of pulses at intervals of approximately 30 millisecondsxc2x120%. Preferably, the interval between pulses of each pulsed signal is adjustable.
In another embodiment of the invention each pulsed signal comprises pulses of duration in the range of 10 microseconds to 200000 microseconds. Advantageously, each pulsed signal comprises pulses of duration in the range of 50 microseconds to 1000 microseconds.
Preferably, each pulsed signal comprises pulses of duration in the range of 100 microseconds to 500 microseconds. Ideally, each pulsed signal comprises pulses of duration of approximately 300 millisecondsxc2x120%. Preferably, the duration of each pulsed signal is adjustable.
In another embodiment of the invention each pulsed signal comprises a plurality of pulses of magnitude in the range of 0 mA to 100 mA. Preferably, the magnitude of each pulse of each pulsed signal is adjustable.
In one embodiment of the invention the attachment means comprises a belt.
In another embodiment of the invention a securing means is provided on the belt for securing the belt around the torso of the subject.
In a further embodiment of the invention a main fastening means is provided corresponding to each main locating means for fastening a corresponding central electrode to the attachment means adjacent the corresponding main locating means.
In a still further embodiment of the invention two secondary fastening means are provided in the attachment means for fastening the respective side electrodes to the attachment means adjacent the corresponding selected secondary locating means.
In one embodiment of the invention each fastening means comprises a stud fastener.
In another embodiment of the invention each stud fastener comprises a female part and a male part, the female part being secured to the attachment means.
In a further embodiment of the invention each stud fastener is electrically conductive so that the female part of the stud fasteners form the corresponding contact means.
Preferably, an exposed surface of the female part of each stud fastener is of electrically insulating material.
Advantageously, the exposed surface of each female part of each stud faster is coated with an electrically insulating coating.
Additionally, the invention provides a stud fastener for use in the device according to the invention, the stud fastener comprises a male part for attaching to a corresponding electrode, and a female part for attaching to the attachment means.
In one embodiment of the invention the male and female parts of the stud fastener engage each other with electrically conductive engagement.
In another embodiment of the invention an exposed external surface of the female part of the stud fastener which abuts the male part of the stud fastener is of electrically insulating material.
In a further embodiment of the invention the electrically insulating material is provided by an electrically insulated coating on the exposed abutting surface.
The invention further provides a method for stimulating abdominal muscles of a subject, the method comprising passing at least one pulsed signal subcutaneously through the subject between selected electrodes of at least three electrodes, one of the at least three electrodes being a central electrode located adjacent the umbilicus of the subject, and the other two electrodes being side electrodes located on the subject spaced apart from the central electrode on respective sides thereof in a general direction towards a corresponding one of the left and right mid-axillary lines of the torso intermediate the rib cage and corresponding left and right iliac crests.
In one embodiment of the invention each side electrode is located towards the mid-point of the corresponding mid-axillary line between the rib cage and the corresponding iliac crest. Preferably, each side electrode is located adjacent the corresponding mid-axillary line. Ideally, each side electrode is located adjacent the mid-point of the corresponding mid-axillary line between the rib cage and the corresponding iliac crest.
Preferably, the central electrode is located on the umbilicus and extends around the umbilicus. Advantageously, the central electrode is located on the umbilicus and extends completely around the umbilicus.
In one embodiment of the invention the central electrode is located on the umbilicus, but with a greater area of the central electrode located below the umbilicus than above the umbilicus.
In another embodiment of the invention the central electrode is located adjacent but not on the umbilicus.
In a further embodiment of the invention the central electrode is located below the umbilicus.
In a still further embodiment of the invention the central electrode is located above the umbilicus.
In another embodiment of the invention the central electrode is located both below and above the umbilicus.
In a still further embodiment of the invention the central electrode is provided by two electrodes, namely, a first central electrode and a second central electrode, both of which are located adjacent the umbilicus. Preferably, the first central electrode is located above the umbilicus and the second central electrode is located below the umbilicus.
In one embodiment of the invention the at least one pulsed signal is applied to the subject so that the signal passes subcutaneously through the subject between at least one selected pair of the at least three electrodes.
In one embodiment of the invention the at least one pulsed signal is applied simultaneously to each of the selected pairs of electrodes. Alternatively, the at last one pulsed signal is applied sequentially to each of the selected pairs of electrodes.
In one embodiment of the invention one of the selected pairs of electrodes comprises one side electrode and the central electrode, and another selected pair of electrodes comprises the other side electrode and the central electrode.
In another embodiment of the invention one of the selected pairs of electrodes comprises the two side electrodes.
In a further embodiment of the invention one of the selected pairs of electrodes comprises one of the side electrodes and one of the first and second central electrodes, and another of the selected pairs comprises the other of the side electrodes and the other of the first and second central electrodes.
In a still further embodiment of the invention one of the selected pairs of electrodes comprises the first and second central electrodes which act as one single electrode and one of the side electrodes, and another of the selected pairs of electrodes comprises the first and second central electrodes which act as one single electrode and the other side electrode.
In a further embodiment of the invention one of the selected pairs of electrodes comprises the first and second central electrodes.
In one embodiment of the invention the pulsed signals applied to the respective pairs of electrodes may be the same or different.
In one embodiment of the invention each pulsed signal comprises a plurality of pulses at intervals in the range of 5 milliseconds to 1000 milliseconds. Preferably, each pulsed signal comprises a plurality of pulses at intervals in the range of 20 milliseconds to 40 milliseconds. Advantageously, each pulsed signal comprises a plurality of pulses at intervals of approximately 30 millisecondsxc2x120%.
Ideally, the interval between pulses of each pulsed signal is adjustable.
In one embodiment of the invention each pulsed signal comprises pulses of duration in the range of 10 microseconds to 200000 microseconds. Preferably, each pulsed signal comprises pulses of duration in the range of 50 microseconds to 1000 microseconds.
Advantageously, each pulsed signal comprises pulses of duration in the range of 100 microseconds to 500 microseconds. Ideally, each pulsed signal comprises pulses of duration of approximately 300 millisecondsxc2x120%. Preferably, the duration of each pulsed signal is adjustable.
In another embodiment of the invention each pulsed signal comprises a plurality of pulses of magnitude in the range of 0 mA to 100 mA. Preferably, the magnitude of each pulse of each pulsed signal is adjustable.
Further the invention provides an electrotherapeutic device for stimulating muscles of a muscle group of a subject, the device comprising a plurality of electrodes for placing on the subject for applying at least one pulsed signal to the subject for stimulating the muscles, a signal generating means for generating the at least one pulsed signal, and a selecting means for selectively selecting the electrodes in electrode pairs and for selectively applying the at least one pulsed signal to the selected electrode pairs for selective stimulation of the muscles of the muscle group.
In one embodiment of the invention the selecting means comprises a switching means for selectively switching the at least one pulsed signal from the signal generating means to the electrodes.
Additionally, the invention provides a method for stimulating muscles of a muscle group of a subject, the method comprising passing at least one pulsed signal subcutaneously through the subject between selected electrodes of at least three electrodes, wherein the electrodes are selectively selected in electrode pairs for selectively stimulating selected muscles of the muscle group.
In one embodiment of the invention the electrode pairs are sequentially selected from the electrodes. Alternatively, the electrode pairs are simultaneously selected from the electrodes.
The advantages of the invention are many. An important advantage of the invention is that it permits relatively accurate placement and alignment of the electrodes on the subject. A particularly important advantage of the invention results from the fact that the device according to the invention permits relatively accurate placement of the electrodes on the subject, and because of this, it has been found that with only three electrodes the device according to the invention provides adequate stimulation to the abdominal muscles, and in particular, to the rectus abdominis and the transversalis and oblique muscles, particularly, for the purpose of toning the muscles. It has been surprisingly found that by locating the central electrode adjacent the umbilicus, and the respective side electrodes towards the corresponding mid-axillary lines to the respective left and right sides of the central electrode good stimulation of the abdominal muscles is achieved. However, it has been found that the closer the side electrodes are located to the corresponding left and right mid-axillary lines the better will be the stimulation. Indeed, it has been found that optimum stimulation is achieved by locating the respective side electrodes on corresponding lines extending from the umbilicus to the mid-point on the corresponding left and right mid-axillary lines between the rib cage and the corresponding iliac crest. In general, it has been found the maximum stimulation of the rectus abdominis, the transversalis and the oblique muscles is achieved when the side electrodes are located on the corresponding mid-axillary line substantially midway between the rib cage and the iliac crest. A further advantage of the invention is achieved where first and second central electrodes are provided, one above and the other below the umbilicus where it has been found that even greater stimulation of the abdominal muscles is achieved, and in particular, stimulation of the rectus abdominis, the transversalis and the oblique muscles.
By providing the side electrodes adjacent the mid-axillary line or spaced part from the central electrode towards the mid-axillary line, but relatively dose to the mid-axillary line the side electrodes apply the pulsed signal or signals to nerve trunks rather than nerve branches which spread out from the nerve trunks. The electrical signals being applied to the nerve trunks, thus spread out through the nerve branches from the nerve trunks, and are thus effective in stimulating a significantly greater area of the muscles of the abdomen than if the electrodes were placed over nerve branches as has been the case heretofore. Additionally by placing the central electrode over or adjacent the umbilicus, and the side electrodes adjacent or relatively close to the mid-axillary line, the spacing between the central and side electrodes is such as to cause the pulsed signal or signals to travel deeper through the subject beneath the fatty tissue. This, thus, results in the pulsed signal or signals being targeted at the deeper muscle controlling nerves, thus providing more efficient stimulation of the muscles. Placing the electrodes relatively closely together, as has been the case heretofore, tends to cause the pulsed signal or signals to pass relatively near the surface of the skin, thus having little affect on the deeper muscle controlling nerves. Indeed, a further advantage of spacing the electrodes apart according to the invention is that the effect of subcutaneous currents on the touch and pain nerves is minimised, thereby minimising discomfort to the subject. Additionally, by providing the side electrodes of size to extend across the lower thoracic nerves and the first lumbar nerves adjacent the mid-axillary line further efficiency is achieved by virtue of the fact that the pulsed signal or signals is applied to the nerve trunks of these nerves. A further advantage of providing the electrodes of reasonable size is that the current density of the pulsed signal or signals passing through the electrodes, and in turn into the subject is minimised, thus, further minimising discomfort resulting from the effect of the subcutaneous current on the touch and pain nerves. Indeed, by providing the electrodes of reasonable size, a higher current may also be applied through the electrodes if such should be desired with minimum discomfort to the subject.
A further advantage of the invention is that it is virtually impossible to incorrectly attach or misapply the electrodes to the subject, and furthermore, there is virtually no danger of the pulsed signals being applied to the wrong electrodes, since the attachment means is pre-wired with the main and secondary connecting means.
A further advantage of the invention is achieved when provision is made for selectively selecting the electrodes into electrode pairs, in that individual muscles of muscle groups may be selectively stimulated, and additionally, if desired different pulsed signals may be applied to different selected electrode pairs.